When cylinder blocks for internal combustion engines are cast from an aluminum alloy, it is common practice to provide a cast-in ferrous liner which forms an interior wall or surface of the combustion chamber and is heat treated or surface hardened in some manner to form a wear resistant surface. For the installation of components adapted to communicate with the combustion chamber, such as a lubrication fitting, a pressure relief valve or a fuel injection nozzle, a port or opening must be formed through both the outer housing or body and the liner. Extreme care must be exercised to insure that the aluminum does not seep through the liner port onto the wear surface of the liner during the casting operation. Also, when forming a threaded opening in the cylinder block, it is desirable that the drilling and tapping operations be performed in a single homogeneous material rather than across the interface of the dissimilar metals of the liner and the cylinder block housing.